The development of fiber optic communication can be roughly divided into 4 stages:
1) the first stage (1g66- 1976), from basic research to commercial applications of the development stage. This period achieved a short wavelength (o.85pum) low rate (up to 45Mbit / s) multimode fiber optic communication system, no relay transmission distance of about 10Km.
2) The second phase (1976-1986), to improve the transmission rate and increase the transmission distance as the research goal and vigorously promote the application of the period of great development. In this period, the development of optical fiber from multimode to single-mode, working wavelength from short wavelength 0.85μm to long wavelength 1.31um and 1.55μm, to achieve the working wavelength of 1.31um, transmission rate of 140-565Mb / s single-mode fiber optic communication system, no relay transmission distance of 50-100km.
3) The third phase (1986-1996), to super-large capacity ultra-long distance as the goal, a comprehensive and in-depth research period of new technologies. In this period, the realization of 1.55μm dispersion-shifted single-mode fiber optic communication system. Using external modulation technology, the transmission rate can reach 2.5- -10Gb/s, no relay transmission distance up to 100- 15okm. laboratory can reach a higher level.
4) The fourth stage (after 1996), the period of great development of vigorous promotion and application. Ultra-high-capacity wavelength division multiplexing (WDM) fiber optic communication system and ultra-long-range optical soliton (Soliton) communication system implementation. Fiber optic communication technology has become a pillar of the information society, has become the backbone of the information "highway", is the user, access network and the future of the world's communications development.
